Pigment concentrates for coloring seeds

ABSTRACT

The present invention relates to the use of a pigment form or pigment concentrate comprising of an organic pigment, and optionally an inorganic filler and/or an organic additive for coloring of seeds. Seeds colored by the dry pigment forms or pigment concentrates show an homogeneous color and in some cases growth promotion effects.

FIELD OF THE INVENTION

[0001] The present invention relates to instant pigment forms andpigment concentrates, in particular pigment concentrates comprising ofan organic pigment, and/or optionally an inorganic filler and an organicadditive, a method for its preparation and the use of the pigmentconcentrate for coloring seeds.

BACKGROUND OF THE INVENTION

[0002] Seeds are often treated to reduce yield losses during cultivationand for enhancing the agronomic and nutritional value of the produce.Such treating agents are for example fungicides, insecticides,rodenticides, nematocides, miticides or bird repellents. Furthermore,many varieties of genetically altered crops are coming to the market.Treated and/or genetically modified seeds must be marked in order todistinguish them from the untreated and unmodified seeds. The marking ofseeds is particularly beneficial for farmers who then can easilydistinguish the chemically treated and modified seeds for plantings frome.g. cereal grains for consumption.

[0003] A number of patents describe processes for the marking andcoating of seeds by active ingredients and film forming compositions.U.S. Pat. No. 5,087,475 discloses a process for the film-coating ofmaterials using a water- and gas-permeable, adhesive film-formingsubstance, which consists of spraying the film-forming substance on seedmaterials and drying the seed materials. The spraying and drying stepsare carried out simultaneously using a compact volume of seed materialsin motion. The film-forming substance is supplied in the form of asolution or a suspension. U.S. Pat. No. 5,470,581 discloses a processfor providing an aqueous film-coating from a combination of maltodextrinand cellulosic polymers for pharmaceutical tablets, candy, cereals andagricultural seeds. The aqueous suspension can be applied by spraying.The aqueous suspension can contain a colorant. U.S. Pat. No. 5,849,320discloses a process for coating a seed with an insecticide.

[0004] U.S. Pat. No. 4,853,429 and 4,881,343 describe an aqueous mediumcontaining a dye or pigment and a binder resin composed of the salt ofchitosan and an organic acid for seed coloring. The patents indicatethat the colorant is used at a concentration of about 0.1 to 10% byweight based on the aqueous medium and exemplifies using Pigment Green7, Pigment Green 128 and Pigment Red 122 at 2.5% concentration. Thepatents do not indicate the form or solids content of said pigments.

[0005] U.S. Pat. No. 5,746,022 discloses a seed color coating using apoly oxyalkylene substituted chromophore in the coating. The coatingcomposition contains a solvent, binder, colorant and other optionaladditives. The coating composition is applied as a film coating byspraying a solution, dispersion and/or suspension onto the seeds. Theaqueous-based coating composition is described as containing 5 to 80parts biologically active agents, 20 to 45 parts water, 1 to 15 partsbinder and 0.1 to 50 parts colorant. In Example II, the coloringcomposition consists of 310 parts lime, 170 parts water, 30 parts poly(vinyl alcohol) binder and 1 part of green colorant (37% solids).

[0006] U.S. Pat. No. 4,272,417 discloses a liquid seed coatingcomposition containing a binding agent, an active ingredient and acoloring agent in a liquid medium including water and a polyol. Thesuggested colorants are selected from dyes, pigments and lakes. Thecoloring agent is selected for solubility and/or dispersibility in theliquid system. The patent does not disclose any means for producing aso-called dispersible pigment. The coloring agent is present at between0.1 to 3 percent by weight, preferably 0.4 percent by weight of thetotal composition. The solids content of the colorant is not provided.

[0007] U.S. Pat. No. 4,368,591 discloses seeds that are coated with anactive ingredient and between 0.035 and 1.8 grams of titanium dioxideper kilogram of seed in either rutile or anatase form. The titaniumdioxide allegedly provides a bright, opaque coating on the seeds. Theactive ingredient and particulate titanium dioxide are applied onto theseeds in an aqueous medium. The particulate titanium dioxide is indispersion in the aqueous medium. The dispersion contains between 10 andabout 100 grams of insoluble titanium dioxide per liter of dispersion.

[0008] U.S. Pat. No. 5,137,747 claims a process for drying a germinativesubstrate of grains or seeds which have been wetted in a coating orsurface film forming treatment by dusting the substrate with a desiccantpowder consisting of at least one alumina silicate and which issubstantially free of components which would interfere with germinationof the substrate. Although these desiccant powders can contain pigmentsdue to the high alumina silicate content they tend to be low in coloringstrength.

[0009] Published PCT application WO 99/66784 discloses a process forcoating seeds with a thin coating of a pigment that selectively allowslight rays having wavelengths of about 570 to 700 nm to passtherethrough, or, in the alternative, selectively reflects light rayshaving wavelengths of about 420 to about 520 nm. The applicantsexemplified seeds that were coated with a red pigment, which reflectedapproximately from 600 to 700 nm, a blue pigment, which reflectedapproximately 400 to 500 nm, and a green pigment, which reflectedapproximately 500 to 570 nm. The green pigment produced the greatestbudding ratio with respect to the selected seed. The application doesnot provide any showing of a control set of seeds in order to assessimprovement without any pigment coating.

[0010] Even though the known processes can deliver marked seeds, theyare often environmentally unfriendly since they use aqueous dyes whichcan cause colored effluents. Most commercially available organic pigmentparticles are not wettable in aqueous mediums and require the additionof surfactants or hydrophilic copolymers. However, current seed coloringsystems have also employed coating compositions that contain aqueouspigment dispersions, which have a low solid pigment concentration.Despite the presence of surfactants, the aqueous dispersions of pigmentcan settle out as function of time. Additionally, such surfactants canhave a negative impact on the growth of the seeds or can negativelyinteract with other active coating ingredients generating an undesirablegel. Furthermore, aqueous pigment dispersions, delivered in drums need alarge, and in winter, heated storing area to avoid Freezing.

SUMMARY OF THE INVENTION

[0011] Applicants discovered, that the above mentioned disadvantages canbe avoided using pigment compositions comprising organic pigments thathave been treated in a particular manner to produce a highly dispersiblepigment concentrate. Examples of such pigment compositions are describedin patents such as for example U.S. Pat. No. 5,584,922 or U.S. Pat. No.5,667,580. Particularly preferred examples are described in U.S. Pat.No. 5,931,997, U.S. Pat. No. 5,843,220 and U.S. Pat. No. 6,063,182. Eachof these patents are incorporated herein by reference. These patentsdisclose pigments that are readily dispersible to color high molecularweight substrates like for example plastics, automotive paints or inks.The patents do not suggest that the stir-in pigments described thereinwould be suitable for coloring seed materials or disclose aqueousdispersions.

DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention describes pigment forms and pigmentconcentrates which can be effectively, and due to their high colorstrength, economically be used for seed coloring. Such pigment forms andpigment concentrates do not have any adverse effect to seeds, but colorthe seeds and additionally can manifest germination-promoting effects.

[0013] The present invention is drawn to a colored seed having anexterior surface that is coated substantially in its entirety with anorganic pigment that is characterized by a masstone reflection spectrumfrom 400 nm to 700 nm having a first peak from 400 nm to 520 nm with amaximum at 460 nm +/−10 nm, a second peak from 540 to 680 nm having amaximum at 630 nm +/−10 nm and a positive slope from 680 to 700 nm.

[0014] In order to measure the reflection spectrum, the inventivepigment is first incorporated into a substrate, such as for example abasecoat/clearcoat paint system like those described in Examples 2A and2D of U.S. Pat. No. 5,931,997. It is the reflection spectrum of thepigmented substrate, such as the coated panel or a pigmented plasticsheet which is measured. The reflection spectra are measured at“complete hide” which means that the substrate is pigmented such thatany background color is not observable. For example, at “complete hide”it is not possible to see the background color of a coated panel or abackground color through a pigmented plastic sheet. A masstonereflectance spectrum is the reflectance spectrum observed when theinventive pigment is the only pigment used to color the substrate.

[0015] When incorporated into an basecoat/clearcoat paint system tocomplete hide, the inventive copper phthalocyanine pigment yields amasstone coated panel that is characterized by a reflection spectrumhaving a maxima above 6 percent at 460 nm +/−10 nm and a reflection at480 nm above 5 percent, a reflection at 620 nm above 4.6 percent and areflection at 700 nm above 4.5 percent. In particular, the masstonereflection spectrum shows a reflection at 480 nm above 5.3 percent, inparticular from 5.3 to 5.4 percent, a reflection at 620 nm above 4.7percent, in particular from 4.7 to 4.9 percent, and a reflection at 700nm above 4.7 percent, in particular from 4.7 to 4.8 percent.

[0016] In general, at least 95 percent of the particles in the pigmentconcentrate have a particle size in the range from 0.1 μm to 9 μm withat least 50 percent of the particles having a particle size in the rangefrom 0.5 μm to 3.5 μm. Based on these average particle size ranges, itis clear that such pigments are used in the form of a pigment crude or aconditioned pigment. Preferably, at least 50 percent of the particleshave a particle size in the range from 0.8 to 2.5 μm. The largestdimension (e.g. length) of the pigment particle is measured to determinethe particle size.

[0017] Particle size is determined by an electron micrograph or by laserdiffraction using a Fraunhofer diffraction instrument. However, electronmicroscopy is a more reliable method for determining the presence ofsmall particles, for example those with a particle size below 0.1 μm.

[0018] The copper phthalocyanine pigment is not platelet-shaped. Inparticular, the preferred pigment concentrate is composed mostly ofpigment particles having a prismatic shape wherein the particles have alength which is more than three times the width and the particlethickness is at least one third the width.

[0019] The preferred pigment form is prepared by direct synthesis or byan appropriate conditioning method, such as, for example,recrystallization of a premilled copper phthalocyanine in an appropriateorganic solvent or mechanically breaking commercially available copperphthalocyanine crude, which generally has needle-prismatic shape and aparticle size distribution wherein about 50 percent or more of theparticles have a particle size in the range from 1.5 to 5 μm, butwherein a significant number of particles, for example, greater than 5percent, are larger than 9 μm, for example, up to 45 μm.

[0020] Although the preferred copper phthalocyanine pigment showsexcellent dispersibility and a remarkably good flocculation resistancefor a beta copper phthalocyanine pigment, in order to further improvethe pigment properties of the inventive copper phthalocyanine pigment,texture-improving agents and/or anti-flocculants are can be addedbefore, during or after the corresponding preparatory process.

[0021] The preferred pigment form is prepared by subjecting an organicpigment, which organic pigment is a pigment crude or a recrystallized,large-particle-size organic pigment, preferably a copper phthalocyanine,to an air jet milling step. Air jet milling is known and described forexample in DE 2042626, U.S. Pat. No. 3,856,215, U.S. Pat. Nos.3,648,936, 3,595,486 and 3,550,868, which are here incorporated byreference. Air jet mills such as the JET-O-MIZER™ or MICRO-JET™ arecommercially available from Fluid Energy Processing and EquipmentCompany, Plumsteadville, Pa. 18949.

[0022] In general, air jet milling selectively reduces the particle sizemainly of those particles in the sample which are outside of the desiredparticle size range. Thus, the average particle size of theair-jet-milled sample usually changes only slightly after the millingstep, but the particle size distribution of the particles in the sampleis within a much narrower range.

[0023] In comparison to other conditioning methods, for example wetmilling, the air jet milling process provides pigment particles withfewer small splinter particles. The pigmentary crystal fragmentsmaintain a clean, practically unbroken surface, as is seen by electronmicroscopy. For this reason, air jet milling yields a pigment withhigher reflection and different flop behavior relative to a pigmentobtained by other known conditioning methods. Since no organic solventsare involved, the air jet milling process is a practical,environmentally friendly conditioning method. The desired particle sizerange is easily achieved by an expert utilizing the appropriateequipment and air pressure. Additionally, depending on the set up, it ispossible to run such a mill continuously. The requisite millingconditions are readily ascertained by measuring the pigment particlesize; for example by an electron micrograph or by laser diffractionusing a Fraunhofer diffraction instrument.

[0024] A preferred embodiment of this aspect of the present invention isthe process wherein at least 95 percent of the particles in theconditioned pigment have a particle size in the range from 0.1 μm to 9μm with at least 50 percent of the particles having a particle size inthe range from 0.5 μm to 3.5 μm. Based on these average particle sizeranges, it is clear that such pigments are used in the form of a pigmentcrude or a conditioned pigment. Preferably, at least 50 percent of theparticles have a particle size in the range from 0.8 to 2.5 μm,especially wherein the conditioned pigment is a copper phthalocyaninepigment, most preferably a beta copper phthalocyanine. Preferably theconditioned copper phthalocyanine pigment is prepared by air jet millinga copper phthalocyanine crude, preferably an alpha or beta copperphthalocyanine crude.

[0025] The present invention alternatively relates to a colored seedhaving a coating that has been prepared by air jet milling from 1 to 40parts by weight of an inorganic filler in the presence of from 60 to 99parts by weight of an organic pigment to yield a uniform blend of theinorganic filler and the organic pigment. In general, after the air jetmilling step is completed the largest dimension of 95% of the particlesin the resulting pigment composition is 18 μm or less, preferably 14 μmor less and most preferably about 7 to 10 μm, when measured for exampleby laser diffraction using a Fraunhofer diffraction instrument.

[0026] The inorganic filler is reduced in particle size in the presenceof the organic pigment and uniformly blended with the organic pigment inthe air jet mill. The organic pigment and inorganic filler are added tothe air jet mill individually, for example as separate streams, or areblended prior to the air jet milling step. Typically, the organicpigment is blended with the inorganic filler prior to the air jetmilling by wet or dry mixing of the components in the proper ratio. Wetmixing is carried out, for example, in the end step of a pigmentpreparatory process, or by blending the filler into an aqueous pigmentslurry. Typically, a wet blended mixture needs to be dried andmicropulverized prior to the air jet milling step. Preferably, theorganic pigment is dry blended with the inorganic filler in a suitablecontainer or in blending equipment, such as the TURBULA mixer from W.Bachofen, Basel, Switzerland, or the P-K TWIN-SHELL INTENSIFIER BLENDERfrom Patterson-Kelley Division, East Stroudsburg, Pa. The organicpigment/inorganic filler blend is then subjected to the air jet millingprocedure described above.

[0027] The pigment compositions are “uniform blends” of the filler andorganic pigment, a uniform blend being a physical mixture of the fillerand pigment wherein the filler particles are evenly distributed in thepigment and mostly uncoated by the pigment. The term “mostly” isintended to mean that although there may be some coated particles in thepigment composition, such coated filler particles do not constitute alarge portion of the filler particles in the pigment composition.Similarly, the exterior surface of the seeds are coated with the pigmentin substantial fashion. The term “physical mixture” means that thepigment and filler particles are distinct from each other, especiallywhen the pigment composition is dispersed.

[0028] Generally, the present pigment compositions comprise from 60 to99 parts by weight of the organic pigment and from 1 to 40 parts byweight of the filler. Preferably, the pigment compositions contain fromabout 65 to 95 parts by weight of the organic pigment and about 5 to 35parts by weight of the filler, most preferably from about 70 to 90 partsby weight of the organic pigment and from about 10 to 30 parts by weightof the filler. The parts are relative to one another and, as to the twocomponents, sums 100 parts by weight.

[0029] The expression “inorganic filler” means a substantiallytransparent inorganic pigment. For example, mica, kaolin, talc,wollastonite and natural or synthetic silica, e.g. glass, are well-knowninorganic fillers that are suitable for use in the pigment compositionsof the present invention. Talc, muscovite mica and kaolin are highlysuitable inorganic fillers. Talc and transparent micas are especiallysuitable for use as an inorganic filler. Of the micas, muscovite,phlogopite, brolite and synthetic micas are the most suitable.

[0030] The inorganic filler is preferably used in its natural form, butincludes treated transparent or semitransparent inorganic fillerpigments, for example a mica treated with a metal oxide, or talc treatedwith an organic aliphatic compound, such as a long chain aliphatic acid.In general, the inorganic filler consists of primary filler particleshaving any geometric shape, but a flaked shape is preferred.

[0031] Especially suitable classes of organic pigments are thephthalocyanines. For example the blue alpha or beta copperphthalocyanine, most preferably a beta copper phthalocyanine or thehalogeneted copper phthalocyanine greens, like C.I. Pigment Green 7 orC.I. Pigment Green 36.

[0032] In general, the inorganic filler has a mean particle size in therange from 4 to 18 μm with 95% of the particles having a largestdimension of 70 μm or less prior to air jet milling. Preferably, 95% ofthe particles have a largest dimension below 60 μm, preferably below 50μm, and a mean particle size in the range from 6 to 15 μm, preferably 8to 12 μm, prior to air jet milling.

[0033] Generally, the organic pigment has an average particle size inthe range of from 0.001 to 30 μm, preferably within the range from 0.005to 3 μm, prior to the air jet milling step. Based on these averageparticle size ranges, it is clear that the organic pigment is used inthe form of a pigment crude or a conditioned pigment. Additionally, theorganic pigment can contain customary additives, such as textureimproving agents, light stabilizers and/or antiflocculating agents.

[0034] The present invention is alternatively drawn to a colored seedhaving an exterior surface coated with at least one layer of a pigmentconcentrate that comprises from 1 to 40 parts by weight of an inorganicfiller and from 60 to 99 parts by weight of an organic pigment relativeto one another wherein said components have not been conditioned by airjet milling. The organic pigment has an average particle size of 0.001to 10 μm. Preferably, the average particle size of the organic pigmentis from 0.005 to 4 μm. Based on these average particle size ranges, itis clear that such pigments are used in the form of a pigment crude or aconditioned pigment. Preferably, the pigment is used in its aqueouspresscake form as obtained, for example, by the isolation of the pigmentafter synthesis or conditioning. The inorganic filler preferably has anaverage particle size from 0.05 to 25 μm, more preferably from 0.1 to 10μm.

[0035] In an alternative embodiment, the colored seed comprises a seedhaving an exterior surface coated with at least one layer of pigmentconcentrate that comprises from 85 to 99.5 parts by weight of an organicpigment, and from 0.5 to 15 parts by weight of a polar polymer orcopolymer having a weight average molecular weight of not more than300,000, relative to one another. Any polar polymer which provides theinstant dispersing pigment behavior according to this invention andwhich preferably is approved by the Environmental Protection Agency canbe used. Preferably, the polar polymer or copolymer is a polyvinylpyrrolidone or copolymer thereof with an average molecular weight ofabove 5000.

[0036] The organic pigment for each of the embodiments can be selectedfrom the group consisting of azo, azomethine, methine, anthraquinone,phthalocyanine, perinone, perylene, diketopyrrolopyrrole, thioindigo,iminoisoindoline, iminoisoindolinone, quinacridone, flavanthrone,dioxazine, indanthrone, anthrapyrimidine and quinophthalone pigments andmixtures thereof.

[0037] The present invention further relates to a process for coloringseeds by contacting a plurality of seeds with a dry instant pigment formor a liquid media containing said pigment concentrate comprising anorganic pigment, as described, above, which has been conditioned by airjet milling.

[0038] The present invention further relates to a process for coloringseeds by contacting a plurality of seeds with a dry instant pigmentconcentrate or a liquid media containing said pigment concentratecomprising from 1 to 40 parts by weight of an inorganic filler and from60 to 99 parts by weight of an organic pigment having an averageparticle size of 0.001 to 10 μm to form a coating thereon. In apreferred aspect, the pigment concentrate and/or inorganic filler hasbeen conditioned by air jet milling. The weights are relative to oneanother.

[0039] An alternative method for coloring seeds comprises contacting aplurality of seeds with a dry pigment concentrate or a liquid mediacontaining said instant pigment concentrate that comprises from 0.5 to15 parts by weight of a polar polymer or copolymer having a weightaverage molecular weight of not more than 300,000 and from 85 to 99.5parts by weight of an organic pigment to form a coating thereon. Theweights are relative to one another.

[0040] The seeds described herein are used to grow plants, fruits orvegetables. The particular type of seed is not important. In general,the seeds will have a somewhat spherical shape, perhaps with flat edgesor sides. The colorant described herein will be applied to the exteriorsurface of the seeds.

[0041] In this application, the expression “dry pigment form or drypigment concentrates” is intended to mean a composition which is used topigment seeds. Thus, the present dry pigment form or pigmentconcentrates do not include the pigmented seeds. Accordingly, theinventive pigment form or pigment concentrates can consist essentiallyof the organic pigment and optionally filler, and are generally powders.However, the inventive pigment form or pigment concentrates can alsocontain specific organic additives for pigment compositions, for examplethe known texture improving agents. The inventive pigment forms orpigment concentrates are capable of forming a substantially uniform andstable aqueous dispersion.

[0042] Any organic pigment can be used according to this invention aslong as it is environmentally friendly and does not negatively impactthe growth or the properties of the seeds or the resulting produce.Suitable classes of organic pigments include the azo, azomethine,methine, anthraquinone, phthalocyanine, perinone, perylene,diketopyrrolopyrrole, thioindigo, iminoisoindoline, iminoisoindolinone,quinacridone, flavanthrone, dioxazine, indanthrone, anthrapyrimidine andquinophthalone pigments; particularly preferred are the organic pigmentswhich have been approved already by the US Environmental ProtectionAgency such as for example certain pigments of the dioxazine,phthalocyanine and azo pigment class or a mixture thereof.

[0043] Notable pigments useful in the present dry pigment concentratesare those pigments described in the Color Index, including the groupconsisting of C.I. Pigment Red 48, C.I. Pigment Blue 15, C.I. PigmentGreen 7 and C.I. Pigment Violet 23 or a mixture thereof.

[0044] Appropriate organic additives are for example the knowntexture-improving agents including fatty acids having at least 12 carbonatoms, and amides, esters or salts of fatty acids. Typical fatty acidderived texture-improving agents include fatty acids such as stearicacid or behenic acid, and fatty amines such as laurylamine, orstearylamine. In addition, fatty alcohols or ethoxylated fatty alcohols,polyols such as aliphatic 1,2-diols or polyvinylalcohol, and polyvinylpyrrolidone, polyacrylic acid and copolymers thereof, epoxidized soybean oil, waxes like carnauba wax. Rosin, rosin acids or rosin acidsalts, hydrogenated rosin and rosin derivatives, resin acids such ashydrogenated abietic acid or resin acid salts are particularly suitableorganic additives.

[0045] Hydrogenated abietic acid, rosin, hydrogenated rosin, rosinderivatives and rosin acid salts are preferred texture-improvingadditives. The rosin acid and resin acid salts are preferably calcium,magnesium, strontium and aluminum salts.

[0046] The organic additive in the dry pigment concentrate is added atthe end of the pigment synthesis step or to the pigment press cake or itis incorporated to the organic pigment/talc blend when it is dry or wetblended. Preferably, these additives are added before the isolation ordrying of the organic pigment after synthesis or conditioning.

[0047] The amount of the texture-improving additive is 0.05 to 30 partsby weight, preferably 1 to 20 parts in 100 parts by weight of the drypigment concentrate according to this invention.

[0048] In an additional aspect of the present invention, the pigmentconcentrate contains a polar organic additive such as the abovementioned polyvinyl alcohol, polyacrylic acid or particularly polyvinylpyrrolidone. Applicants discovered that the addition of the polarpolyvinyl pyrrolidone further enhances the wetability of the pigment.

[0049] Therefore, such pigment concentrates are instantly dispersed whenadded to an aqueous liquid media and do not need a special dispersionstep utilizing an expensive equipment like high speed mixers ordispersion mills.

[0050] Preferably, a polyvinyl pyrrolidone approved by the EnvironmentalProtection Agency such as polyvinyl pyrrolidone with a molecular weightof above 5000 is incorporated into an aqueous pigment/inorganic fillerslurry which is then spray dried to generate low dusting, easilyflowable and easily wetable pigment concentrates. Particularly preferredpigment concentrates containing the polar organic additive can beprepared in accordance with the teachings in U.S. Pat. No.6,063,182,which is incorporated herein by reference.

[0051] As described more fully therein, the particularly preferredpigment concentrates are obtained by spraying an aqueous dispersion. Ahighly concentrated pigment presscake is slurried in any suitable deviceat temperatures between 5 to 90° C., preferably 20 to 60° C., such as,for example, a Cowles™ disperser, in the presence of the aqueousadditive solution as illustrated in the examples below to obtain ahomogeneous aqueous dispersion. Suitable conditions for spray drying thehomogeneous aqueous dispersions can then easily be determined by aperson skilled in the art.

[0052] Low viscosity aqueous pigment dispersions with a solids contentof above 15% or, depending on the pigment and polymeric additive oradditive mixture, solids contents of 20% and above can be easilygenerated. Despite the high pigment concentration, these pigmentdispersions have the advantage that they are liquid, easily flowable andideally suited for spray drying. Spray drying is a well known dryingtechnology in the chemical industry. Any equipment which is conventionalfor spray drying for example a disc or nozzle spray dryer can be used tospray dry the inventive pigment compositions. Suitable commerciallyavailable equipment includes the BOWEN BLS spray dryer from Bowen or theNIRO ATOMIZER from NIRO Company. Due to their high solids content, thepigment dispersions are dried rapidly and economically by spray drying,yielding unique pigment compositions composed of microgranules. Theadditives according to this invention are homogeneously distributed inthe stir-in pigment compositions and also serve as the binder for themicrogranules.

[0053] Typically, the microgranules have a size in the range of from 1to 3000 μm, preferably from 3 to 1000 μm when suspended in awater-immiscible solvent such as xylene and observed under the lightmicroscope. They can have any shape. The shape and size of themicrogranules are influenced by several parameters such the kind andparticle size of the pigment, the kind and concentration of the additiveor additive mixture respectively, as well as the spray drying conditionsand the spray dryer equipment. The microgranules are generally lessdusty and can be more easily handled than conventionally dried andmicropulverized pigments.

[0054] The amount of the polar organic additive is 0.05 to 15 parts byweight, preferably 1 to 10 parts in 100 parts by weight of the drypigment concentrate according to this invention.

[0055] Remarkably, the dry instant pigment forms and pigmentconcentrates according to the present invention show an outstandingdispersibility and compatibility behavior to the seed media. Thus, theseeds are easily colored and marked by the inventive pigment forms andpigment concentrates providing a consistent colored material with a longshelf life. The colorant layer is provided on the seed oversubstantially their entire surface resulting in homogeneously coloredseed.

[0056] Growth promotion is a most valuable effect because it enhancesthe yield of the produce. Thus, the faster the germination the lessprone are seed losses due to birds or bad weather conditions like strongrain, wind or dryness. Growth promotion for grass for example isparticularly useful on fields and slopes to cut the erosion, on sportfields or lawns for safety and aesthetic reasons respectively. Aparticularly strong growth effect was observed on grass seeds coloredwith a pigment form or pigment concentrate using a beta copperphthalocyanine that had been conditioned using air jet milling, which isdescribed above.

[0057] Any number of techniques and equipment known to those skilled inthe art of seed coating may be applied for the seed coloring by the drypigment forms or pigment concentrates. The process may be continuous orbatch, and typically involves tumbling of the seeds in the presence ofthe present dry pigment forms or pigment concentrates.

[0058] An alternative application process involves a liquid media inwhich the pigment forms or pigment concentrates have been dispersed.Examples of suitable liquid media include an aqueous, organic oraqueous/organic media, which may additionally contain biologicallyactive components, binders or other coating ingredients. Preferably, theliquid media is primarily an aqueous medium with optionally only minoramounts of organic materials. Most preferably, the mixture ofconcentrate and liquid media produces a dispersion having an aqueouscontinuous phase with pigment concentrate suspended therein, which areoptionally coated with a surfactant or dispersant. The dispersion shouldbe substantially free of organic, water-immiscible solvents, which wouldproduce an emulsion. The concentration of the pigment concentrate (on adry basis) is about 0.1 to 10 percent of the overall composition, morepreferably 0.1 to 3, most preferably, 0.1 to 1 percent. Preferably thepigment concentrates are treated with a polar organic additive asdescribed above when practicing this embodiment of the invention. Theinventive instant pigment concentrates are quickly wetted and due to itshigh pigment concentration extremely economic. The reduced level ofliquid media lowers the generation of wastewater and reduces the energyrequirements for producing a “dry” seed.

[0059] In yet another method, the dry pigment form or pigmentconcentrate or a liquid media as described above is applied onto a seedthat has been coated with an aqueous and/or organic liquid film-formingsubstance that can optionally contain an active ingredient, defoamers,and a binder. Examples of active ingredients are fungicides,insecticides, rodenticides, herbicides, bird repellants, nematocides,miticides, growth regulants, and nutrients. Alternatively, the seed iscoated with said film-forming substance and then subsequently providedwith a coloring layer using the dry instant pigment concentrate orpigment concentrate-containing liquid media described herein. Analternative means for applying the colorant includes the steps ofapplying uncolored seeds over a surface and subsequently spraying anaqueous-based solution containing the selected pigment onto thesurface-laid seeds.

[0060] Furthermore, the liquid media containing the above mentionedactive ingredients, defoamers or binders can be directly colored by theaddition of an active coloring amount of the dry pigment form or pigmentconcentrate and then be applied to the seeds.

[0061] The use of dry instant pigment form or pigment concentrateprovide characteristic coloristic pigment properties to seeds such as ahigh opacity and a homogenous intense color in an effective, economicaland environmentally friendly manner by eliminating or reducing liquidwaste product. The resulting colored seeds also offer the advantage thatthe colorant layer is substantially nonsoluble souluble in water andtherefore will not be eliminated due to exposure to rain or humidconditions. The colored seeds also exhibit improved color fastness whenexposed to light relative to seeds that have been colored with dyes.Additionally, the resulting dry pigment layer can advantageously promotegrowth.

[0062] The following examples further describe some embodiments of theinvention, but do not limit the scope of the invention. In the examples,all parts are by weight unless otherwise indicated.

EXAMPLES Example 1

[0063] 300 grams IRGALITE Red C2B from Ciba Specialty Chemicals Corp.which is a rosin and resin acid salt treated C.I. Pigment Red 48.2 isblended on a roller gear with 100 grams Canfil 7 from Canada Talc Ltd.,which has an average particle size of 7 μm.

[0064] The resulting blend is micro pulverized in an assemble micropulverizer (The BANTAM, type G 90 from the American Marietta Company)using a 0.027 inch round hole screen and a rotating speed of 14500 RPMyielding an easily dispersible dry pigment concentrate whichhomogeneously colors seeds in a strong red color.

Example 2

[0065] The procedure of Example 1 is repeated using instead of Canfil 7,Ultra talc 609 from Barrets Mineral Inc. which has an average particlesize of 0.8 μm as an inorganic filler yielding a dry pigment concentratewhich is ideally suited for homogeneously coloring seeds in a consistentred color.

Example 3

[0066] The procedure of Example 2 is repeated using instead of IRGALITERed C2B IRGALITE Blue LGE from Ciba Specialty Chemicals Corp. which is ahydrogenated rosin treated C.I. Pigment Blue 15.3 yielding a dry pigmentconcentrate which is ideally suited for homogeneously coloring seeds ina consistent blue color.

Example 4

[0067] 1000 grams IRGALITE Blue GE granules from Ciba SpecialtyChemicals Corp., which is a hydrogenated rosin treated C.I. Pigment Blue15.3 is pulverized in an assemble micro pulverizer (The BANTAM, type G90 from the American Marietta Company) using a 0.125 inch round holescreen and a rotating speed of 7000 RPM.

[0068] 900 grams of the above resulting pulverized pigment is blendedwith 225 grams Canffil 7 and air jet milled with a Micro-Jet® air jetmill (from Fluid Energy Aljet, Plumsteadville Pa.) to a top particlesize of below 10 μm. The resulting blue dry pigment concentrate isideally suited for homogeneously coloring seeds in a consistent bluecolor.

[0069] Grass seeds colored with such a blue pigment concentrate show theadvantage of a notably faster growth behavior versus the uncolored ordifferently treated seeds.

Example 5

[0070] Example 3 is repeated using instead of C.I. Pigment Blue 15.3 ahydrogenated rosin treated C.I. Pigment Green 7 yielding a dry pigmentconcentrate which is ideally suited for homogeneously coloring seeds ina consistent green color

Example 6

[0071] A 4 liter WARING Blender from Cole-Parmer Instrument Company ischarged with 2286 grams aqueous presscake containing 802 grams dryweight isoindolinone pigment IRGAZIN YELLOW 3 RLTN (C.I. Pigment Yellow110 from Ciba Specialty Chemicals Corp., Newport Del.).

[0072] In a one liter glass beaker 59.6 grams of an aqueouspolyvinylpyrrolidone solution (LUVISKOL K30 from BASF Corp.) aredissolved in 200 ml water. Then 80.2 grams ULTRA Talc 609 from BarrettsMinerals Inc. are added into the aqueous resin solution and stirreduntil completely wetted.

[0073] The aqueous talc/resin mixture is added to the yellowisoindolinone pigment presscake in the WARING blender. The mixture isblended at medium to high speed generating an easily flowable liquidyellow pigment dispersion.

[0074] Two batches of the above aqueous yellow pigment dispersion arecombined, followed by spray drying in a pilot plant spray dryer (theBOWEN BLS from Bowen) yielding 1.78 kg yellow pigment concentrate in amicrogranule form which can instantly be incorporated into an aqueousliquid media employed to coloring seeds homogeneously in a yellow color.Preparation of liquid media is described more fully in example 8.

Example 7

[0075] The above procedure is repeated using instead of IRGAZIN Yellow3RLTN 3050 grams of a press cake containing 1059 grams of the C.I.Pigment Red 48.2, IRGALITE Red 2BP from Ciba Specialty Chemicals Corp.,88.2 grams LUVISKOL K30 and 130 grams Ultratalc 609 yielding a redpigment concentrate in a microgranule form which can instantly beincorporated into an aqueous liquid media employed to coloring seedshomogeneously in a red color.

Example 8

[0076] One gallon porcelain testing jug is charged with one quartdistilled water. Using a laboratory stirrer, 20 oz equal blends XL(R-[(2,6-dimethylphenyl)-methoxyacetylamino]-propionic acid methylester) an TL (N-(2,6-dimethylphenyl)-N-(methyloxyacetyl)alanine methylester)-aprons and one teaspoon (about 1.5 grams) of the blue pigmentconcentrate prepared according to Example 4 are added and stirred untila homogeneous pigment dispersion is generated. In a roller tumblecontaining 2 pounds of control fescue the above blue dispersion is addedand rolled for 30 minutes. The mixture is removed and the liquid isdecanted. The solids are placed on a drying tray and dried with forcedair for 72 hours, resulting in commercially acceptable intense bluestained seeds.

[0077] Surprisingly, fescue growth was observed with the above coloredblue seeds within 72 hours, whereas the uncolored seeds were inert.

Example 9

[0078] 500 grams of beta copper phthalocyanine crude (from PHTHALCHEMPCL GROUP Inc. Cincinnati, Ohio 45232) having a needle-prismaticparticle shape and an average particle size of from 2.0-3.0 μm, butcontaining particles of up to 44 μm, is air jet milled such that thelarger particles are reduced to a particle size of below 9 μm on aMICRO-JET® air pulverizer from Fluid Energy Aljet, Plumsteadville Pa.

[0079] The resulting product shows a particle size distribution of 30%from 0.2 to 0.8 μm, 40% from 0.8 to 2.1 μm and 30% from 2.1 to 8 μmmeasured by a laser diffraction particle analyzer (MICROTRAC).

[0080] The electron micrograph shows particles with a marked prismaticshape wherein 50 percent of the particles display a length of from 2 to4.5 μm length and a width of from 0.3 to 1.1 μm. The crystals show clearbroken edges with few small splinter particles below 0.2 μm.

[0081] The dry copper phthalocyanine pigment form is ideally suited forhomogeneously coloring seeds in a consistent blue color. Surprisingly,fescue growth was observed with such colored blue seeds within 48 hours,whereas the uncolored seeds were inert.

I/we claim:
 1. A colored seed having an exterior surface coated with atleast one layer comprising an instant pigment form or pigmentconcentrate wherein at least 95 percent of the pigment particles in thecorresponding pigment form or pigment concentrate have a particle sizein the range from 0.1 μm to 9 μm with at least 50 percent of the pigmentparticles having a particle size in the range from 0.5 μm to 3.5 μm. 2.A colored seed having an exterior surface coated with at least one layercomprising an instant pigment concentrate comprising from 1 to 40 partsby weight of an inorganic filler and from 60 to 99 parts by weight of anorganic pigment having an average particle size of 0.001 to 10 μmrelative to one another.
 3. A colored seed according to claim 1 ,wherein the pigment particles have been conditioned by air jet milling.4. A colored seed according to claim 1 , wherein the organic pigment andinorganic filler are conditioned by air jet milling.
 5. A colored seedof claim 1 , wherein the average particle size of the organic pigment isfrom 0.005 to 4 μm.
 6. A colored seed of claim 2 , wherein the averageparticle size of the inorganic filler is from 0.05 to 25 μm.
 7. Acolored seed of claim 6 , wherein the average particle size of theinorganic filler is from 0.1 to 10 μm.
 8. A colored seed having at leastone layer comprising an instant pigment concentrate that comprises from85 to 99.5 parts by weight of an organic pigment, and from 0.5 to 15parts by weight of a polar polymer or copolymer having a weight averagemolecular weight of not more than 300,000.
 9. A colored seed accordingto claim 8 , wherein said polar polymer or copolymer is a polyvinylpyrrolidone or copolymer thereof with an average molecular weight ofabove
 5000. 10. A colored seed of claim 1 , wherein the organic pigmentis selected from the group consisting of azo, azomethine, methine,anthraquinone, phthalocyanine, perinone, perylene, diketopyrrolopyrrole,thioindigo, iminoisoindoline, iminoisoindolinone, quinacridone,flavanthrone, dioxazine, indanthrone, anthrapyrimidine andquinophthalone pigments and mixtures thereof.
 11. A colored seed ofclaim 1 , wherein the organic pigment is selected from the groupconsisting of azo, phthalocyanine and dioxazine pigments and mixturesthereof.
 12. A colored seed of claim 1 , wherein the organic pigment isa copper phthalocyanine or a halogeneted copper phthalocyanine.
 13. Acolored seed of claim 1 , wherein the pigment of the organic pigmentform is an air-jet milled copper phthalocyanine.
 14. A colored seed ofclaim 2 , wherein the organic pigment is a copper phthalocyanine or ahalogeneted copper phthalocyanine and the inorganic filler is mica,kaolin, talc, wollastonite, natural silica, synthetic silica or mixturesthereof.
 15. A colored seed of claim 14 , wherein the inorganic filleris talc.
 16. A colored seed of claim 14 , wherein said pigmentconcentrate further comprises a texture improving agent is a fatty acid,a fatty amine, a fatty alcohol or ethoxylated fatty alcohol, analiphatic 1,2-diol or polyvinylalcohol, a polyvinyl pyrrolidone,polyacrylic acid and copolymers thereof, an epoxidized soy bean oil, awax, a rosin, a rosin derivative, a resin, a resin acid or a resin acidsalt.
 17. A colored seed according to claim 16 , wherein said textureimproving agent is a polyvinyl pyrrolidone or copolymer thereof with anaverage molecular weight of above
 5000. 18. A process for coloring seedscomprising contacting a plurality of seeds with a dry pigmentconcentrate or a liquid media containing said pigment form or pigmentconcentrate that comprises a pigment form or pigment concentrate whereinat least 95 percent of the pigment particles in the correspondingpigment form or pigment concentrate have a particle size in the rangefrom 0.1 μm to 9 μm with at least 50 percent of the pigment particleshaving a particle size in the range from 0.5 μm to 3.5 μm.
 19. A processfor coloring seeds comprising contacting a plurality of seeds with a drypigment concentrate or a liquid media containing said pigmentconcentrate that comprises from 1 to 40 parts by weight of an inorganicfiller and from 60 to 99 parts by weight of an organic pigment having anaverage particle size of 0.001 to 10 μm to form a coating thereon.
 20. Aprocess for coloring seeds comprising contacting a plurality of seedswith a dry pigment concentrate or a liquid media containing said pigmentconcentrate that comprises from 0.5 to 15 parts by weight of a polarpolymer or copolymer having a weight average molecular weight of notmore than 300,000 and from 85 to 99.5 parts by weight of an organicpigment to form a coating thereon.
 21. A process according to claim 18wherein a plurality of unpigmented seeds are contacted with the drypigment form or pigment concentrate or liquid media containing saidpigment concentrate by spraying after said unpigmented seeds are appliedto a surface.
 22. A process according to claim 19 wherein a plurality ofunpigmented seeds are contacted with the dry pigment form or pigmentconcentrate or liquid media containing said pigment concentrate byspraying after said unpigmented seeds are applied to a surface.
 23. Aprocess according to claim 20 wherein a plurality of unpigmented seedsare contacted with the dry pigment form or pigment concentrate or liquidmedia containing said pigment concentrate by spraying after saidunpigmented seeds are applied to a surface.